Crystal structure and hydrogen storage properties of ZrNbFeCo medium-entropy alloy

Autor(es)

Fontana, Gabriel L. B. G. ; Edalati, Payam ; Dangwal, Shivam ; Edalati, Kaveh ; Strozi, Renato B. ; Floriano, Ricardo

• Tipo de documento: Artigo Científico
• Fonte: INTERMETALLICS; v. 176, p. 9-pg., 2025-01-25.

Resumo

To make hydrogen a more viable energy carrier, various solutions for hydrogen storage have been developed, with significant recent progress in developing new high-entropy alloys (HEAs) that exhibit attractive hydrogen storage properties. In this paper, we investigated the crystal structure and hydrogen storage properties of a new medium-entropy alloy (MEA) ZrNbFeCo, designed using a combination of semi-empirical parameters and thermodynamic calculations via the CALPHAD method. The alloy was synthesized by arc melting under an argon atmosphere and subsequently characterized using comprehensive techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These analyses revealed the presence of a major C14 Laves phase, with a compositional gradient and grain sizes ranging from microscale to nanoscale. The hydrogen storage properties were evaluated using pressure-composition isotherms (PCI) and kinetics curves. After a simple activation procedure, the alloy formed a C14 hydride and exhibited excellent properties to act as a vessel for hydrogen storage at room temperature. Under these conditions, the alloy was able to absorb up to 1.2 wt% of hydrogen (hydrogen-to-metal ratio of H/M similar to 0.9), with fast absorption kinetics, reaching around 87 % of its maximum capacity after just 60s. The alloy also exhibited full reversibility and great stability through multiple absorption-desorption cycles, absorbing an average content of 1.1 wt% of hydrogen (H/M similar to 0.82) after 8 cycles. The present results demonstrate that it is possible to practically employ semiempirical and thermodynamics calculations, originally developed for HEAs, to develop new MEAs that exhibit appropriate microstructure and excellent hydrogen storage properties at room temperature. (AU)

• Processo FAPESP: 22/01351-0 - Estudo dos mecanismos da reação metal-hidrogênio em ligas multicomponentes com estrutura de fase laves hexagonal C14
• Beneficiário: Ricardo Floriano
• Modalidade de apoio: Auxílio à Pesquisa - Regular